[U-Boot] U-Boot DFU test and Ctrl+C

Hey guys,

As I use the DFU tests more and more, I keep hitting what I'm pretty sure is a false failure in the tests. Sometimes the tests fail at:

  u_boot_console.wait_for('Ctrl+C to exit ...')

and the last bit of the console log is: Starting download: [#################################################################] finished! unable to read DFU status #File System is consistent file found, deleting update journal finished File System is consistent update journal finished 65 bytes written in 12380 ms (0 Bytes/s) =>

So perhaps we should make the test look for the prompt itself rather than 'Ctrl+C' ? Thanks!